Sealing unit, particularly for electric connectors

ABSTRACT

A sealing unit about an elongated element, particularly a cable of an electric connector, and presenting first and second elastically deformable sealing elements facing each other, in use, on either side of the elongated element, and each having complementary first and second portions. The sealing elements are pressed against each other so that the first and second portions cooperate in sealing manner with each other, at least one of the first and second portions being deformed by the other portion to cooperate in sealing manner with the elongated element.

TECHNICAL FIELD

The present invention relates to a sealing unit about one or moreelongated elements such as cables, pipes or the like, and isparticularly, though not exclusively, suitable for insertion between thecasing and one or more cables of an electric connector, to whichapplication the following description refers purely by way of example.

BACKGROUND OF THE INVENTION

The electric cable of sealed electric connectors is normally sealed bymeans of a sealing element having a through opening through which thecable is fitted. The sealing element may be a straightforward rubberring for a single cable, as described for example in U.S. Pat. No.5,069,639, or a multiple seal with a number of holes for respectivecables, as described for example in U.S. Pat. No. 4,460,227. As theefficiency of the sealing element depends on its exerting a certainamount of pressure on the cable, the section of the opening must besmaller than the cross section of the cable to produce a certain amountof radial forcing when the cable is assembled.

Known sealing elements of the above type present several drawbacks.

One way of assembling the connector is to insert the cable through thesealing element before crimping the terminal on to the cable, whichsolution, however, involves a fairly complex, time-consuming assemblysequence. Alternatively, the sealing element may be assembled beforehandinside the casing, in which case the electric terminal, already crimpedto the cable, must be fitted through the opening in the seal when theterminal is inserted inside the casing. On account of the small sectionof the opening in the seal, such a solution may result in severedistortion of the seal, and in tearing or cutting of the edge of theopening, thus impairing sealing efficiency in actual use. What is more,subsequent removal and reassembly may result in further damage, to theextent that the seal must eventually be replaced, with all thedisadvantages this entails in terms of time and money.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sealing unit,particularly for an electric connector, designed to overcome thedrawbacks typically associated with known seals of the aforementionedtype.

According to the present invention, there is provided a sealing unitabout an elongated element comprising first and second elasticallydeformable sealing elements facing each other and gripped against eachother and against the elongated element interposed between the sealingelements. The sealing elements comprise respectively at least a firstand at least a second portion complementary in shape, at least one ofthe portions being deformable by the other to cooperate in sealingmanner with the elongated element.

BRIEF DESCRIPTION OF THE DRAWINGS

Two preferred, embodiments of the present invention will now bedescribed by way of example with reference to the accompanying drawings,in which:

FIGS. 1 and 2 show schematic partial views in perspective of a sealingunit in accordance with the teachings of the present invention and intwo different operating positions;

FIG. 3 shows a partially sectioned longitudinal view of an electricconnector featuring a pair of sealing units according to the presentinvention; and

FIG. 4 shows a cross section of the FIG. 3 connector, comprising aportion a along line IVa—IVa, and a portion b along line IVb—IVb in FIG.3.

PREFERRED EMBODIMENT

Number FIGS. 1 and 2 shows a sealing unit 1 comprising a pair of sealingelements 2, 3, which are placed together and pressed against each otherto cooperate in sealing manner with a number of parallel electric cables4 (only one shown in FIG. 1) interposed between elements 2 and 3.

Elements 2 and 3 are molded from elastomeric material, and compriserespective shaped surfaces 5, 6 facing and cooperating with each other.Each of surfaces 5, 6 presents a number of first portions 7 and secondportions 8 defining bands of surfaces 5, 6 extending transversely inrelation to cables 4 and alternating in a direction parallel to cables4. Portions 7, 8 of element 2 are offset axially in relation to portions7, 8 of element 3, so that a portion 7 of one element mates with aportion 8 of the other.

Portions 7 and portions 8 are complementary in shape. More specifically,first portions 7 comprise a number of pairs 9 of sealing lips 10; thelips 10 in each pair 9 define a C-section seat 11 of a depth greaterthan the diameter of cables 4, and housing a portion of a respectivecable; and the adjacent lips 10 of two adjacent pairs 9 are separated bya C-section gap 12 shallower than seats 11. Second portions 8, on theother hand, present an undulated contour defined by a number of crests13 located at gaps 12 of adjacent first portions 7, and alternating witha number of grooves 14 located at seats 11 of adjacent first portions 7.

Second portions 8 are sunk in relation to first portions 7 so as to forma shoulder 15 between the bottom of seat 11 and the bottom of adjacentgroove 14. Lips 10 present a substantially trapezoidal axial section;and the lips 10 of adjacent portions 7 define respective gaps 16 alsopresenting a substantially trapezoidal section but slightly less thanthe section of lips 10 when undeformed.

Sealing elements 2, 3 present respective flat supporting faces 17opposite surfaces 5, 6 and which cooperate in sealing manner withrespective pairs of gripping elements (not shown) between which unit 1is compressed in use.

Unit 1 operates as follows.

In FIG. 1, sealing elements 2, 3 are shown in the open position facingeach other to permit insertion of cables 4 (only one shown) betweenrespective surfaces 5, 6.

Cables 4 are inserted so as to engage seats 11 in portions 7 of eachelement 2, 3 when elements 2, 3 are placed together and pressed againsteach other (FIG. 2) to mate surfaces 5 and 6. Pairs 9 of lips 10 ofportions 7 of one element 2 or 3, which almost entirely surround arespective portion of cable 4, fit inside the corresponding grooves 14of respective portions 8 of the other element 3 or 2; and, at the sametime, crests 13 of each portion 8 engage in forced manner the gaps 12between pairs 9 of lips 10, so that lips 10 in each pair 9 are deformedabout respective cable 4 and cooperate end to end.

Lips 10 thus provide for sealing the entire periphery of the cable, withthe exception of the portion at which they cooperate end to end; whichportion, however, is located at shoulder 15 defined by the adjacentportion 7 and which provides for preventing any infiltration. Thealternating arrangement of portions 7 and 8 therefore defines alabyrinth seal for ensuring absolutely airtight sealing of cables 4;which performance is further improved by the axial force produced by thetrapezoidal section of lips 10 and dimensional interference withrespective gaps 16.

FIGS. 3 and 4 show an electric connector 19 featuring a pair of sealingunits 20 in accordance with the teachings of the present invention.

Connector 19 comprises an insulating casing 21 in turn comprising a mainbody 22 with two rows of cavities (not shown) housing respectiveelectric terminals 23; and two shells 24 snapped together on either sideof an intermediate wall 25 of body 22 separating the two rows ofcavities and projecting from body 22 so as to separate the two rows ofcables 4 of respective terminals 23.

Each shell 24 defines with wall 25 a chamber 29 housing a respectivesealing unit 20. Each unit 20 comprises a sealing element 2 and asealing element 3 with respective surfaces 5, 6 as described withreference to unit 1 in FIGS. 1 and 2; and elements 2, 3 are compressedagainst each other between respective shell 24 and wall 25, andcooperate in sealing manner with opposite sides of cables 4. Shells 24are secured to each other by means of elastic snap-on fasteners, and areretained on wall 25 in the direction parallel to cables 4 by retainingmeans not shown.

To ensure stable transverse positioning of elements 2, 3 and enhance thesealing effect due to interaction of portions 7 and 8, wall 25 andshells 24 are conveniently undulated and defined by a number of equallyspaced projections 27 cooperating with respective recesses 28 formed insurfaces 17 of sealing elements 2, 3 at crests 13 of portions 8 and gaps12 of portions 7.

The advantages of units 1 and 20 according to the present invention areas follows.

By virtue of the sealing unit being formed in two separate parts betweenwhich the cables are inserted, it may be assembled and disassembled withthe terminals already crimped to the respective cables 26, with no needto force the terminals through small-section openings as with knownone-piece seals. Moreover, when gripped together against the cable, thecomplementary shape of the two sealing elements causes them to flex intosealing contact with the cable. And finally, the axially alternatingarrangement of portions 7 and 8 defines a labyrinth seal ensuringsubstantially airtight sealing of the unit.

Clearly, changes may be made to units 1 and 20 as described andillustrated herein without, however, departing from the scope of thepresent invention. For example, changes may be made to the number ofportions 7, 8; to the number of cables 4 for sealing; or to the shape oflips 10 and respective seats 11.

What is claimed is:
 1. A sealing unit about an elongated element,comprising first and second elastically deformable sealing elementsfacing each other and gripped against each other and against saidelongated element interposed between them, said sealing elementscomprising respectively at least one first portion and at least onesecond portion complementary and intermatable in shape, at least one ofsaid portions being deformable by the other of said portions tocooperate in a sealing manner to form a fluid-tight seal with saidelongated element.
 2. The sealing unit claimed in claim 1, wherein saidfirst portion comprises at least one pair of sealing lips defining aseat for said elongated element, and said second portion comprises atleast one groove for receiving said sealing lips and deforming themagainst said elongated element.
 3. The sealing unit claimed in claim 2,wherein said first portion comprises a plurality of said pairs ofsealing lips cooperating with respective said elongated elements andseparated by respective gaps, said second portion having an undulatedcontour defined by a plurality of grooves alternating with a pluralityof crests cooperating in a forced manner with said gaps of said firstportion.
 4. The sealing unit claimed in claim 3, wherein each of saidsealing elements has a plurality of said first and second portionsalternating in a direction parallel to said elongated elements.
 5. Thesealing unit claimed in claim 4, wherein said second portions of eachsaid sealing element have a recessed profile in relation to said firstportions, a shoulder being formed between bottoms of seats in each saidfirst portion and bottoms of grooves in an adjacent said second portion.6. The sealing unit claimed in claim 4, wherein said sealing lips ofsaid first portions of each said sealing element are so shaped as toengage in forced manner a gap defined between the sealing lips of a pairof said first portions of the other said sealing element.
 7. A sealingunit for an electric connector and which is interposed between a casingand at least one cable of said connector, said sealing unit comprisingfirst and second elastically deformable sealing elements facing eachother on either side of said cable and being pressed against each otherand against said cable, said sealing elements comprising at least onefirst portion and at least one second portion complementary andintermatable in shape, at least one of said first and second portionsbeing deformable by the other of said portions to cooperate in a sealingmanner to form a fluid-tight seal with said cable.
 8. An electricconnector comprising an insulating casing, at least one electricterminal housed in said casing and presenting a respective cable, andsealing means interposed between said cable and said casing, saidsealing means comprising at least one sealing unit as claimed in claim1.
 9. The electric connector claimed in claim 8, wherein said sealingunit is compressed between a fixed portion and a movable element of saidcasing.
 10. The connector claimed in claim 9, wherein said sealingelements of said sealing unit comprise respective shaped supportingsurfaces presenting recesses at gaps and crests of said first and secondportions, said fixed portion and said movable element of said casinghaving respective numbers of projections cooperating with said recesses.11. A sealing unit about an elongated element, comprising first andsecond elastically deformable sealing elements facing each other andgripped against each other and against said elongated element interposedbetween them, said sealing elements comprising respectively at least onefirst portion and at least one second portion complementary in shape, atleast one of said portions being deformable by the other of saidportions to cooperate in a sealing manner to form a fluid-tight sealwith said elongated element, wherein said first portion comprises atleast one pair of sealing lips defining a seat for said elongatedelement, and said second portion comprises at least one groove forreceiving said sealing lips and deforming them against said elongatedelement.